do all mistresses/masters expect cbt
Nope. Just like not all submissives like or want it.
how far can things go
As far as both parties wish to or are able to take it
can any one give suggestions that I could try myself before letting a mistress/master down?
Don't be worried about letting people down as if you and a master/mistress have good communication, you won't let them down and they will understand how far you are willing and able to go.

Read some of the stories involving cbt, the toys used and various techniques being described. If as you say this is a limit of a sort, no master or mistress will be expecting full on caning cbt on your first go, and nor should they!.

I hope a male sub with some experience will come along and give practical advice.

Good luck, let us know how you get on.